Examples of an input device for inputting information to an information processing apparatus such as a personal computer (PC) are typically a keyboard (keypad) for inputting character information, a pen tablet for inputting image information and a mouse for inputting positional information. These input devices are appropriately selected and used depending on the purpose. More specifically, an input device depending on the type of information to be input is selectively connected to a PC in each case. Alternatively, information is input to a PC through various types of input devices selectively connected to the PC.
On the other hand, it has been proposed that a detachable input unit having a keyboard and a mouse on the upper surface and a tablet on the rear surface is used by arbitrarily turning upside down so that information can be input in various form depending on the purpose. Further, it has been proposed that an input function of a touch screen (touch panel) is selectively switched by changing the display on the touch screen display.
However, the above-mentioned related art needs to prepare the various types of input devices depending on various types of the information to be input. This kind of situation inevitably causes the high cost of equipment. Further, the input devices need to be placed near the PC. Therefore, there is a problem of the space for installation. Furthermore, it is necessary to selectively connect the input device to be used to the PC according to the input device to be used. Thus, the handling becomes difficult.